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At least 919 records · Page 51Linked to original sources
PubMed2003

Posterior capsule dehiscence during phacoemulsification and manual extracapsular cataract extraction: comparison of outcomes.

PURPOSE: To compare the intraoperative behavior and postoperative outcomes of posterior capsule dehiscence during phacoemulsification and during manual extracapsular cataract extraction (ECCE). SETTING: L.V. Prasad Eye Institute, Hyderabad, India. METHODS: This study was a retrospective chart review of consecutive cases of posterior capsule dehiscence over 2 years in patients having phacoemulsification or manual ECCE. A chi-square test was used for statistical comparison of the results in the 2 groups. RESULTS: In the 127 eyes with posterior capsule dehiscence, the incidence of vitreous prolapse was comparable between the 2 groups (phacoemulsification, 61.6%; ECCE, 62.7%). In the phacoemulsification group, vitreous prolapse occurred more frequently if nuclear fragments were present at the time of posterior capsule dehiscence than if they were present during cortex removal (P =.05). Posterior dislocation of nuclear fragments occurred in 4 eyes in the phacoemulsification group. Increased anterior uveitis in the early postoperative period occurred more frequently in the ECCE group (P =.02). The visual outcomes were similar between the 2 groups. CONCLUSIONS: Even though differences existed between the intraoperative factors influencing the management of posterior capsule dehiscence during phacoemulsification and ECCE, the final anatomic and visual outcomes were comparable.

Capsulorhexis↗
PubMed2003

In vitro model for the study of human posterior capsule opacification.

PURPOSE: To develop and evaluate a model for the organ culture of human lens capsules that reduces problems inherent in preexisting models for the study of in vitro posterior capsule opacification (PCO). METHODS: Human lenses (N = 110) were isolated from donor eyes and supported externally within a lens holder system by medical-grade cyanoacrylate glue, allowing visualization of the entire capsular bag. After capsulorhexis and lens extraction were performed, the capsule specimens were maintained at physiological conditions for up to 4 weeks. The area of lens epithelial cell (LEC) coverage over the posterior capsule surface was determined objectively on a daily basis using a graticule. Lens epithelial cell behavior was correlated with clinical data and other in vitro PCO models. RESULTS: Cyanoacrylate glue did not appear to be toxic to LECs at the concentration used. The amount of viable epithelium after nuclear extraction was dependent on the age and postmortem time of the specimen. Viable LEC cultures were obtained from eyes up to 9 days postmortem. The time from death to culture or from enucleation to culture did not influence LEC viability if it was fewer than 5 days. The LEC proliferation rates and confluence times were age dependent and correlated closely between pairs of eyes. CONCLUSIONS: Results show that the lens holder model is a more physiological method for supporting the capsule and is a robust, reproducible system for the study of LEC migration and proliferation. It allows visualization within the entire capsular bag. Intraocular lenses can be implanted in this system in a way that more closely resembles the in vivo scenario. This model can be used to evaluate therapeutic measures to prevent PCO.

Adolescent↗
PubMed2003

Role of posterior capsulotomy with vitrectomy and intraocular lens design and material in reducing posterior capsule opacification after pediatric cataract surgery.

PURPOSE: To study the effect of primary posterior capsulotomy with anterior vitrectomy (PPC + AV) and intraocular lens (IOL) design and material on the development of posterior capsule opacification (PCO) after pediatric cataract surgery. SETTING: Tertiary care institution in India. PATIENTS: Sixty-four eyes of 52 children ranging in age from 3 months to 12 years who had cataract extraction with IOL implantation were prospectively evaluated for a minimum postoperative period of 2 years. METHODS: Thirty-two eyes received a hydrophobic acrylic lens with a truncated, square edge and 32, a single-piece poly(methyl methacrylate) (PMMA) lens that was not heparin surface modified. Sixteen eyes in each IOL group had PPC + AV; in the remaining 16 eyes in each group, the posterior capsule was left intact. RESULTS: Postoperatively, 25 eyes in the intact capsule group and 5 in the PPC + AV group developed PCO; the difference between groups was significant (P<.05). Of eyes with an intact capsule, 12 with an acrylic IOL and 13 with a PMMA IOL developed PCO (P>.05). In the PPC + AV group, 2 eyes with an acrylic IOL and 3 with a PMMA IOL developed PCO (P>.05). Overall, 14 eyes with an acrylic lens and 16 eyes with a PMMA lens developed PCO (P>.05). After surgery, there was a significant short-term delay in the development of PCO in the acrylic group (14 eyes; mean 6.66 months +/- 1.57 [SD]) compared to the PMMA group (16 eyes; mean 3.16 +/- 0.83 months) (P<.05). CONCLUSIONS: It is the management of the posterior capsule rather than IOL design and material that influences the incidence of PCO after cataract surgery in children. Development of PCO in the postoperative period was delayed with a hydrophobic acrylic IOL with square edges compared with a PMMA lens without square edges.

Acrylic Resins↗
PubMed2004

Tissue damage at anterior capsule edges after continuous curvilinear capsulorhexis, high-frequency capsulotomy, and erbium:YAG laser capsulotomy.

PURPOSE: To compare the effect of erbium:YAG laser photocapsulotomy (ELC), continuous curvilinear capsulorhexis (CCC), and high-frequency capsulotomy (HFC) on anterior capsule edges using light microscopy (LM) and transmission electron microscopy (TEM). SETTING: Department of Ophthalmology, Department of Histology and Embryology II, University of Vienna, Vienna, Austria. METHODS: Five anterior capsule membranes were obtained experimentally by ELC, which was performed with the Oertli MicroLaser photoemulsification tip in eyes from 5 human cadavers. Thirty anterior capsule membranes were obtained during cataract surgery by CCC (n = 15) or, in cases with poor or missing red fundus reflexes, by HFC (n = 15). Continuous curvilinear capsulorhexis was performed conventionally with a manual, bent, 27-gauge cannula, and HFC was performed according to Klöti. Membranes were processed and examined by LM and TEM according to standard procedures. RESULTS: The edges obtained by ELC showed mild signs of denaturation and mechanical disruption, tears, and micro-tears. Lens capsule edges obtained by CCC were smooth with no irregularities in any specimen; the edges were beveled anteriorly to posteriorly with no evidence of tearing. Edges produced by HFC were considerably wider; the surfaces showed distinct denaturation, preformed tears, and micro-tears. The edges were surrounded by a nonhomogeneous mass, which consisted mainly of denatured lens capsule material. CONCLUSIONS: Of the 3 techniques, CCC produced the mildest tissue damage. The histological damage at ELC edges was relatively mild and intermediate compared with that seen at CCC and HFC edges. These observations suggest that ELC is an appropriate option for anterior capsulotomy in cataract surgery.

Aged↗
PubMed1995

Corneal endothelial cell loss caused by detached opacified anterior lens capsule in the anterior chamber.

From 1984 to 1986, we performed cataract surgery through a 1.5 mm anterior capsule hole in 77 eyes. The hole was enlarged to 6.0 mm by a slit incision, and an intraocular lens was implanted into an almost completely intact capsular bag. Twelve (16%) eyes developed severe postoperative anterior capsule opacification. The opacified central anterior capsule, approximately 5 mm in diameter, was detached by can-opener anterior capsulotomy using a neodymium:YAG laser and fell into the inferior anterior chamber. Inferior corneal endothelial cell loss occurred in nine of the 12 eyes within 20 months after detachment; in six of the nine, inferior corneal endothelial cell density decreased 50% more than central cornea cell density. This method will be unsuitable for treating the extensive anterior capsule opacification that will occur when endocapsular cataract surgery that retains most of the lens capsule is widely performed in the future.

Aged↗
PubMed1994

Cataract surgery in children with capsulorhexis of anterior and posterior capsules and heparin-surface-modified intraocular lenses.

Cataract surgery was performed in 21 eyes in 14 children (one to 12 years, 5.6 +/- 4.0 [mean +/- SD]). Cataract surgery was standardized and included capsulorhexis of the anterior capsule, irrigation/aspiration of the nucleus and cortex, puncture of the posterior capsule, injection of sodium hyaluronate (Healon GV, 14 mg/ml) between the posterior capsule and the vitreous, and capsulorhexis of the posterior capsule. At the end of the procedure, a heparin-surface-modified (HSM) poly-(methyl methacrylate) intraocular lens (IOL) was implanted in the capsular bag. Follow-up ranged from four to 16 months. No complications such as the appearance of vitreous in the anterior chamber occurred during surgery. A mild postoperative inflammation was seen in all cases. Opacification of the visual axis was seen in one eye ten months after surgery. Posterior synechial formation was seen in one eye. Our results suggest that capsulorhexis of the anterior and posterior capsules with implantation of an HSM IOL in the capsular bag is a safe procedure in children and produces good postoperative results.

Cataract Extraction↗
PubMed1988

Specular microscopy of the anterior lens capsule after endocapsular lens implantation.

Endocapsular phacoemulsification and complete in-the-bag intraocular lens (IOL) fixation was performed on 77 eyes. Specular microscopy of the anterior lens capsule was performed postoperatively, and the process of anterior capsule opacification after endocapsular cataract surgery was classified. Lens epithelial cells on the inner surface of the anterior lens capsule, facing the optical portion of the IOL, underwent a diffuse fibrosis. In more peripheral areas, where the anterior and posterior capsules were tightly adherent, the regularly proliferating lens epithelial cells retained their polygonal shape. These findings suggest the possibility of retaining the transparency of the anterior lens capsule postoperatively by refilling the capsular bag to apply internal pressure.

Aged↗
PubMed1996

Posterior capsule opacification and capsulotomy rates with taco-style hydrogel intraocular lenses.

PURPOSE: To evaluate posterior capsule opacification (PCO) formation and neodymium: YAG (Nd:YAG) laser capsulotomy results in eyes with an logel intraocular lens (IOL). SETTING: First University Hospital, Vienna, Austria. METHODS: A retrospective study was done of 108 eyes with one of three types of an logel IOL that had decreased vision from PCO and required posterior capsule discission. RESULTS: In general, in eyes with sulcus-placed IOLs, a Soemmering's ring formed and the capsulorhexis rim tightly adhered to the posterior capsule, sealing the capsular bag periphery. Elschnig pearls had broken the barrier, invading the retrolental space. In eyes with bag-placed IOLs, there was a gap between the IOL and posterior capsule in which Elschnig pearls had accumulated. This gap frequently extended beneath the flanges to the periphery of the capsular bag, allowing residual lens epithelial cells to proliferate and migrate centrally. CONCLUSION: The logel lenses led to a high incidence of regeneratory PCO within the gap between the lens and capsule that might be the result of the properties of the lens' hydrogel material rather than its design.

Cataract↗
PubMed1996

Lens epithelial cell migration onto the posterior capsule in vitro.

PURPOSE: To investigate lens epithelial cell (LEC) proliferation on the posterior capsule in an in vitro model. SETTING: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. METHODS: We cultured the cells remaining on the postoperative capsular bag and expanded the capsule with an open poly(methyl methacrylate) ring to simulate actual postoperative conditions. Using human and rabbit cadaver eyes, we monitored the migration and proliferation of LECs onto the postoperative capsular bag by time-lapse videomicroscopy. RESULTS: The remaining viable cells migrated onto the posterior capsule through the equator and directly from the anterior capsule. The cells typically proliferated in a monolayer because of contact inhibition of cell movement and division, but they proliferated in a multilayer at some regions where nonviable cells had accumulated and there were capsular folds. CONCLUSION: A means to block both routes of cell expansion must be developed to prevent LEC migration onto the posterior capsule.

Adolescent↗
PubMed1997

Cell proliferation on the outer anterior capsule surface after extracapsular lens extraction in rabbits.

PURPOSE: To use light microscopy to evaluate the presence and distribution of cells that proliferate on the outer surface of the anterior capsule after experimental lens extraction in rabbit eyes. SETTING: Research Laboratory, Department of Ophthalmology, Wakayama Medical College, Wakayama, Japan. METHODS: Extracapsular lens extraction, with or without implantation of a poly(methyl methacrylate) intraocular lens, was performed in 10 adult albino rabbits under general anesthesia. Animals were killed 1 month postoperatively. Each eye was embedded in paraffin and examined by light microscopy. RESULTS: A capsular bag composed of the anterior and posterior capsules was observed. Mononuclear cells, presumed to be lens epithelial cells (LECs), had proliferated in the space between the capsules as well as on the outer surface of the anterior capsules, in association with an accumulation of extracellular matrix. CONCLUSION: After lens extraction, LECs migrated to and proliferated on the anterior surface of the anterior capsule.

Animals↗
PubMed1997

Radiofrequency diathermy capsulorhexis of the anterior and posterior capsules in pediatric cataract surgery: preliminary results.

PURPOSE: To assess the effectiveness of radiofrequency diathermy capsulorhexis in preventing opacification of the posterior capsule in pediatric cataract extraction. SETTING: The Children's Hospital, Dublin, Ireland. METHODS: Radiofrequency diathermy capsulorhexis to the anterior capsule followed by injection of sodium hyaluronate behind the posterior capsule and primary posterior capsule diathermy capsulorhexis were performed in 14 eyes of 7 children requiring cataract surgery. RESULTS: Six patients had bilateral congenital and 1 patient bilateral developmental cataracts. Ten eyes (5 patients) received heparin-surface-modified intraocular lenses, and 4 eyes (2 patients) were left aphakic. There were no intraoperative complications, and only mild anterior segment inflammation was noted postoperatively. CONCLUSION: With follow-up from 7 to 16 months (mean 12.1 months), our results showed no epithelial regrowth or opacification of the posterior capsule following diathermy capsulorhexis.

Cataract↗
PubMed1998

Anterior capsule contraction with foldable silicone intraocular lenses.

PURPOSE: To examine the causes signs, and symptoms of anterior capsule contraction syndrome and the response to neodymium YAG (Nd:YAG) anterior capsulotomy. SETTING: Madigan Army Medical Center, Tacoma, Washington, USA. METHODS: This retrospective review comprised 70 cases of phacoemulsification with foldable plate-haptic silicone intraocular lens (IOL) implantation. Patients who developed anterior capsule contraction postoperatively, defined as the anterior capsule being visible through an undilated pupil, had a radial anterior capsulotomy with an Nd:YAG laser. Variables analyzed were visual acuity, subjective complaints, associated inflammation, and IOL decentration. RESULTS: Ten eyes of 9 patients (14%) developed anterior capsule contraction and had Nd:YAG laser radial anterior capsulotomy. Three of 9 patients reported decreased visual acuity and glare. Two other patients had chronic anterior chamber inflammation unresponsive to steroids after surgery that resolved after Nd:YAG anterior capsulotomy. Intraocular lens decentration was observed in 3 patients before the Nd:YAG capsulotomy. Posterior lens dislocation occurred in 1 patient after capsulotomy and required surgical lens exchange. CONCLUSION: One-piece foldable silicone IOLs may not provide enough peripheral capsule expansion.

Foreign-Body Migration↗
PubMed1999

Experimental staining of the anterior lens capsule in albino rabbits.

PURPOSE: To study the value and safety of staining the anterior lens capsule in albino rabbits. SETTING: Ophthalmology Department, Cairo University, and Ophthalmic Pathology Department, Research Institute of Ophthalmology, Cairo, Egypt. METHODS: The experiment was divided into 3 stages. First, the capacity of different concentrations of crystal violet solution to stain the anterior lens capsule of postmortem albino rabbit eyes was tested. The toxicity of different concentrations of the dye (2% to 0.25%) was then tested to determine the highest concentration that was nontoxic to the cornea and trabecular meshwork. The third step was to detect possible toxicity of lower concentrations (0.1% to 0.05%). Different dye concentrations were injected into the anterior chamber of the rabbit eyes. The eyes were examined after 1 and 3 days, 1 week, and 1 month using light microscopy and scanning and transmission electron microscopy. RESULTS: Different concentrations of crystal violet stained the anterior lens capsule, allowing for easy capsulorhexis. The use of the 2% and 1% concentrations was accompanied with irreversible damage to all corneal layers. The use of the 0.5% concentration caused damage to stromal keratocytes and endothelium. The use of the 0.25% concentration did not damage any corneal layer or the trabecular meshwork. Lower concentrations of 0.1% and 0.05% also stained the capsule, providing good visibility for successful capsulorhexis, and were less toxic to the corneal endothelium. CONCLUSION: Staining the anterior lens capsule with 0.25% to 0.05% concentrations of crystal violet solution caused no injury to the cornea or trabecular meshwork in albino rabbit eyes.

Animals↗
PubMed1999

Effect of expandable full-size intraocular lenses on lens centration and capsule opacification in rabbits.

PURPOSE: To study the effects of expandable, hydrogel, full-size lenses (FSLs) on lens centration and posterior capsule opacification (PCO) in the rabbit model. SETTING: Center for intraocular Lens Research, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Small FSLs designed for human eyes were implanted unilaterally in 20 rabbit eyes. Lens centration and PCO in these eyes were compared with those in eyes with conventional poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) or aphakia in the fellow eyes. In a second experiment, medium-size or large FSLs designed for rabbit eyes were implanted in 20 rabbit eyes and the results compared with those in eyes with conventional PMMA IOLs. Slitlamp examination of all eyes was performed regularly, after enucleation, gross inspection and microscopic studies were performed. RESULTS: Decentration of FSLs occurred in the presence of an anterior capsule tear or very large capsulorhexis. Posterior capsule opacification developed only at sites where the implanted lens was not in contact with the capsule. Aphakic eyes and looped IOLs developed Soemmering's rings peripherally. In eyes with small FSLs, PCO developed between the lens and the center of the posterior capsule, whereas in eyes with large FSLs, only small amounts of central PCO developed. Retained high-viscosity viscoelastic material had no effect on PCO development. CONCLUSIONS: Complete refilling of the capsular bag by a full-size IOL was associated with excellent centration and only a small degree of PCO. Elastic lenses may thus serve as a starting point for the development of an artificial lens with accommodative function.

Animals↗
PubMed1994

A simple procedure to demonstrate the presence of the O-antigen capsule in enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli O111 bacteria very often produce a capsule-like polysaccharide exhibiting the same chemical composition as the O-specific chains of their lipopolysaccharide and being designated as O-antigen capsule. In this paper, a new simple procedure is described for the detection of this capsule polymer. O-antigen capsule polysaccharide and lipopolysaccharide of bacterial extracts were electrophoretically separated in agarose cetavlon gel, blotted onto nitrocellulose membranes and visualized by immunological methods. As a result of this procedure, the O-antigen capsule can be detected as a spot completely separated from the LPS (Figs. 1 and 2). Consequently, this method allows a clear discrimination of K+ and K- strains.

Agglutination↗
PubMed2000

Oral bioavailability of active principles from herbal products in humans. A study on Hypericum perforatum extracts using the soft gelatin capsule technology.

The oral absorption of two known active principles of Hypericum perforatum, namely hyperforin and hypericin, was studied in an open, single dose, two-way, randomized, cross-over study involving 12 healthy subjects (six males and six females). Alcoholic Hypericum extract (300 mg, containing 5% hyperforin and 0.3 % hypericin) was administered in the morning after 12 hours fasting. The formulation was administered as softgel capsules containing, inter alia, soya oil together with the herbal extract. A second standard formulation in two piece hard gelatin capsules was also used for comparison purposes. Blood was sampled from the subjects at different times after drug administration and the plasma was analysed according to published analytical methods for the determination of hyperforin and hypericin. Peaks of plasma concentration, Cmax of hyperforin were 168.35 ng/ml +/- 57.79 for the soft gelatin formulation (CV=34.32, n=12) and 84.25 ng/ml +/- 33.51 for the hard gelatin capsule (CV=39.77, n=12). The Tmax values for hyperforin were 2.50 h +/- 0.83 for the soft gelatin formulation compared to 3.08 h +/- 0.79 for the reference formulation, whereas the total AUC were respectively 1482.7 h x ng/ml +/- 897.13 and 583.65 h x ng/ml +/- 240.29. As for hypericin, plasma levels were detectable in approximately half of the subjects treated. However also in this case the soft gelatin capsules exhibited a higher individual absorption when compared with the corresponding data for the hard gelatin capsules.

Administration, Oral↗
PubMed2003

Unsuspected ileal stenosis causing obscure GI bleeding in patients with previous abdominal surgery--diagnosis by capsule endoscopy: a report of two cases.

Peri-anastomotic ulcerations may occur in patients with previous abdominal surgery. They may present only with obscure GI bleeding. We report two cases in whom capsule endoscopy identified postsurgical stenoses with ulcers as the cause of obscure GI bleeding. Case 1. A 57-year-old male operated on in 1970 for a post-traumatic diaphragm hernia followed by displacement of the caecum in the upper left abdominal quadrant. Case 2. A 32-year-old female with a salpingectomy for tuberculosis (1978) followed by segmental ileal resection for intestinal obstruction. Both patients had undergone extensive work-up including bidirectional endoscopies and enteroclysis with negative results. Capsule endoscopy with the GIVEN diagnostic system was done. Ileal stenoses with mucosal ulcers in dilated prestenotic loops were observed in both cases. The capsule was retained at the stenosis site, requiring ileal resection and anastomosis. Pathology reports showed mucosal ulcers. In case 2, tuberculosis was ruled out by tissue and faecal polymerase chain reaction and culture. Ileal stenoses with prestenotic ulcerations causing GI bleeding may occur in patients with previous abdominal surgery. Capsule endoscopy may clarify the diagnosis and shorten the diagnostic work-up. However, these patients should be warned that capsule retention requiring surgery might occur.

Adult↗
PubMedDate not supplied

Loading the multilayer dextran sulfate/protamine microsized capsules with peroxidase.

Stable polyelectrolyte capsules were produced by the layer-by-layer (LbL) assembling of biodegradable polyelectrolytes, dextran sulfate and protamine, on melamine formaldehyde (MF) microcores followed by the cores decomposition at low pH. The mean diameter of the capsules at pH 3-5 was 8.0 +/- 0.2 microm, which is more than that diameter of the templates (5.12 +/- 0.15 microm). With pH growing up to 7-8, the capsules enlarged, swelling up to the diameter 9-10 microm. The microcapsules were loaded with horseradish peroxidase. Seemingly, peroxidase is embedded in the gellike structure in the microcapsule interior formed by MF residues in the complex with polymers used for LbL coating as proved by Raman confocal spectroscopy. The amount of finally incorporated peroxidase increased from 0.2 x 10(8) to 2.2 x 10(8) peroxidase molecules per capsule with pH growing from 5 to 8. The pH shifts causing changes in capsule swelling and the replacement of solutions without pH shifts lead to the protein loss. The encapsulated peroxidase showed a high activity (57%), which remained stable for 12 months.

Biocompatible Materials↗